1. Field of the Invention
This invention relates to a connecting assembly for an ignition plug in a double overhead cam shaft type gasoline engine, in which a high tension cable is connected to the ignition plug and to a method for producing the same.
2. Statement of the Prior Art
In an overhead valve (OHV) type gasoline engine as well as a double overhead cam shaft (DOHC) type gasoline engine, an ignition plug is disposed at a deep position in the engine. Such a kind of gasoline engine is provided with a connecting assembly for the ignition plug such as the one disclosed in, for example, Japanese Utility Model Public Disclosure No. 55-188985 (1980), in order to connect a high tension cable to the ignition plug.
For convenience of explanation, the above known connecting assembly for the ignition plug will be described below by referring to FIG. 13.
FIG. 13 is a longitudinal sectional view of the connecting assembly 100 for the ignition plug P.
The connecting assembly 100 for the ignition plug P includes an ignition plug connecting terminal 101 and a plug cap 102.
The ignition plug connecting terminal 101 is attached to an end of a high tension cable C by pressing work and has a shape adapted to be mechanically mated with and electrically contacted with a terminal part Pa of the ignition plug P. Also, the ignition plug connecting terminal 101 is provided with an outwardly extending annular projection 101a on the outer periphery thereof.
The plug cap 102 is made of a synthetic insulating resin material and is inserted into a plug bore 103a formed in an engine cover 103. The plug cap is also provided on the interior with a shoulder 102a which engages with the annular projection 101a of the ignition plug connecting terminal 101.
The high tension cable C is inserted into the plug cap 102 through a proximal end of the cap. After a top end of the high tension cable C passed through a top end of the plug cap 102 has been pressed and connected to the ignition plug connecting terminal 101, the top end of the high tension cable C is retracted in the plug cap 102 until the annular projection 101a of the ignition plug connecting terminal engages with the shoulder 102a.
On the other hand, the terminal part Pa of the ignition plug P can be inserted into the plug cap 102 through a distal end of the cap. The terminal part Pa of the ignition plug P inserted in the plug cap 102 is electrically connected to the ignition plug connecting terminal 101 supported in the plug cap 102.
The plug cap 102 fixes the high tension cable C in the cap at the position where the ignition plug connecting terminal 101 contacts with the ignition plug P. The plug cap 102 is secured to the engine cover 103 through a waterresistant cap 104.
In the above conventional connecting assembly 100 for the ignition plug P, the ignition plug connecting terminal 101 is held in the plug cap 102 or the ignition plug P by engaging the annular projection 101a with the shoulder 102a in the plug cap 102.
However, since the ignition plug connecting terminal 101 is fixed incompletely in the plug cap 102 in the conventional connecting assembly 100, the ignition plug connecting terminal 101 and the ignition plug are vibrated at different frequencies on account of various vibrations caused during driving. Consequently, a head of the ignition plug P is subjected to a great wear.